Animated agents in learning systems are lifelike, computerized characters that simulate a human relationship and are designed to facilitate learning in interactive environments. The most common animated agent interface consists of an animated face, a cartoon character, or a human-like virtual agent. They draw their strength from the naturalness of the living-organism metaphor in terms of both cognitive accessibility and communication style. The role of animated agents in learning systems is to accurately model the kinds of dialogues and interactions that occur during apprenticeship learning and one-on-one tutoring. Additionally, animated agents in learning systems play a significant part in stimulating social interaction that can facilitate learners to engage in the learning task and consequently to enhance learning in computer-based environments. As a result, they can ...